Virtual concatenation is used today in synchronous communication networks, such as Synchronous Optical Network (SONET) based networks or Synchronous Digital Hierarchy (SDH) based networks, to combine multiple synchronous channels carrying low rate payload into a single synchronous channel carrying high rate payload. A mechanism to enable dynamic virtual concatenation for increasing or decreasing capacity of a link without service affecting is developed today under the Link Capacity Adjustment Scheme (LCAS).
However, there are still several problems that are not addressed by LCAS. For example, Applicants' unpublished pending Israel Patent Application IL 149,323 filed on Apr. 24, 2002 addresses one such problem of dynamically adding channels to and removing channels from a group of virtually concatenated channels in cases where network delays associated with the channels to be added and removed are different from network delays associated with the group.
Another problem that is not addressed by LCAS is enabling of dynamic application of changes to a group of virtually concatenated channels in communication systems that support protection mechanisms. Solutions to such a problem are considered as highly desired.
Some aspects of technologies and related art that may be useful in understanding the present invention are described in the following publications:
a contribution T1X1.5/2000-157R1 dated Jul. 10-14, 2000 of Lucent Technologies to the T1 Standards Project—T1X1.5 which proposes a justification for a variable bandwidth allocation (VBA) methodology for SONET virtually concatenated SPEs (SPE—Synchronous Payload Envelope);
a contribution T1X1.5/1999-098 dated Apr. 9, 1999 of Lucent Technologies to the T1 Standards Project T1X1.5 which describes higher order SONET virtual concatenation;
a contribution T1X1.5/2000-199 dated Oct. 9-13, 2000 of Lucent Technologies to the T1 Standards Project—T1X1.5 which describes a proposed link capacity adjustment scheme (LCAS) for SONET virtually concatenated SPEs; and
the following chapters in The Communications Handbook, CRC Press & IEEE Press, 1997, Editor-in-Chief Jerry D. Gibson: Chapter 39 on pages 542-553, and Chapter 40 on pages 554-564.
The disclosures of all references mentioned above and throughout the present specification are hereby incorporated herein by reference.